CLINICAL QUESTION
What is the neural effect of neoadjuvant treatment on patients with locally advanced thyroid cancer and recurrent laryngeal nerve (RLN) paralysis?
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July 2024BOTTOM LINE
Carcinomatous neural invasion can be a reversible process, and recovered nerves may demonstrate normal morphology and electrophysiological activity.
BACKGROUND: In cases of locally aggressive thyroid cancer, neoadjuvant treatment can allow regression of the tumor away from critical structures and may enable less morbid resection with optimized surgical margins. Recovery of RLN function after neoadjuvant treatment challenges the long-held assumption that carcinomatous neural invasion is irreversible.
STUDY DESIGN: Retrospective review.
SETTING: Division of Thyroid and Parathyroid Endocrine Surgery, Department of Otolaryngology–Head and Neck Surgery, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston.
SYNOPSIS: Researchers identified six adult subjects (50% female; mean age 69 years) from multiple institutions who 1) were diagnosed with advanced thyroid carcinoma of any histology, underwent pretreatment flexible fiberoptic examination (FOE) of the larynx with documentation of vocal fold paresis or paralysis; 2) received targeted therapy and underwent FOE during/after treatment with confirmed return of vocal fold (VF) mobility; and 3) underwent surgery with use of intra-operative nerve monitoring (IONM). Descriptive analysis examined the following parameters for recovered nerves: nerve morphology, characterized as Type A (involving epineurium only) versus Type B (extending beyond epineurium); proximal stimulability (normal, abnormal, or absent); and surgical management (resection versus preservation). At baseline, all six subjects had unilateral vocal fold paralysis (VFP). The median duration of treatment until the return of VF function was three months. All nerves were noted to have Type A morphology. Proximal stimulability was normal in four subjects, abnormal in one, and absent in one. Recovered RLNs were surgically preserved in five subjects. Authors note that these results reinforce the importance of laryngoscopy in initial evaluation and in subsequent assessment during neoadjuvant treatment to guide surgical decision-making. Study limitations include its retrospective nature and small sample size.
CITATION: Russell MD, Abdelhamid Ahmed AH, Feng Z, et al. Recovery of recurrent laryngeal nerve function with neoadjuvant treatment: neural characterization [published online ahead of print January 24, 2024]. Laryngoscope: doi.org/10.1002/lary.31304.